2001 Chevy Silverado Error codes PO300, PO327 and PO440

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P0300 Random/Multiple Cylinder Misfire Detected

P0327 Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)

P0440 Evaporative Emission Control System Malfunction

Suspect a faulty knock sensor or faulty wiring to knock sensor. With a faulty knock sensor the computer may also pick up a random misfire, which will throw the code P0300 as well. However, code P0440 is not related to the first two codes. For this one, inspect the gas cap to make sure it is tightened properly and also inspect the gas cap seal. If OK here, inspect the vacuum line from the throttle body to the purge solenoid for leaks. The best way is with a smoke machine. There could also be an issue with the purge solenoid or the electrical connection to it. Post your results and I will follow up.

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Except for the 4.3L and 8.1L engines, yes it is in the valley under the intake manifold. For the 4.3L engines it is on the rear of the engine block and for the 8.1L engines it is on the left side of the engine, under the exhaust manifold.

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Glad you got it fixed, thanks for the info!

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